Thanks, Curt, but I don't air is the problem. After installing it, I noticed that the translucent tubing on the new gauge was 2/3 air, but worked fine. I think the column of oil pressure pushes the air into the gauge, maybe compresses it a bit, but the gauge indicates the pressure of the oil (air). After all, you don't prime the tube, so you have to start with the air which is captive in the tube? But I admit that I could be 100% wrong about this.
